How to properly implement nested queries?

Question

MySQL

You need to count the number of elements returned in the subquery. If you write the subquery by hand, everything works fine, but if you try to build a query using QueryBuilder, you get an error.
The subquery is written manually:

$qb3 = $this->createQueryBuilder('c')
                   ->select('COUNT(c.id)')
                   ->where('c.id IN (SELECT cl.id FROM Acme\AppBundle\Entity\ClassC cl INNER JOIN Acme\AppBundle\Entity\ClassP p WHERE p.var1 = :var1 AND p.var2 = cl.id GROUP BY cl.id)')
                   ->setParameter('var1', $var);

The subquery is built via QueryBuilder:

$qb = $this->createQueryBuilder('c');
$qb->select('COUNT(c.id)')
      ->where(
          $qb->expr()->in(
              'c.id',
              $this->createQueryBuilder('cl')
                      ->select('cl.id')
                      ->innerJoin('Acme\AppBundle\Entity\ClassP', 'p')
                      ->where('p.var1 = :var1')
                      ->setParameter('var1', $var)
                      ->andWhere('p.var2 = cl.id')
                      ->groupBy('cl.id')
                      ->getDQL()
         )
     );

Both options return exactly the same DQL.

Answer 1

Move the parameter initialization for the nested builder to the parent one:
$qb->setParameter('var1', $var)